This from 5741 Duck...
London Underground is always very insistent that passengers "Please use all the available doors".
Getting on/off/on/off... etc until you've used all available doors takes ages.
And that was on a quiet day. Imagine if everybody obeyed this in the rush hour: even if they all started at the same end of the train it would be bedlam.
But I don't think LUL really means it, as the doors closed while I was on the platform between cars.
UPDATE: This from Theydon Bois...
Whilst I am still greatly enjoying the mental image of 5741 Duck working along the train in a heroic effort to comply with the perceived instruction to use all the doors, I do rather suspect that LU is addressing passengers collectively rather than individually and that 5741 Duck is misinterpreting this for (undoubted) comic effect.
Mind you, that does not therefore mean the announcement is sensible or necessary, just that it is somewhat more sensible than 5741 Duck would have us believe.
I wonder how long you would get away with trying to do this before the BTP's finest felt obliged to come and discuss it with you.
And whether citing the LU announcement would be an effective defence under Rail Rozzer interrogation.
I do hope it would.